#include <iostream>
#include <algorithm>
#define MAX 55

using namespace std;

int father[MAX];    //记录各节点的父节点
int m[MAX][MAX];    //存储采用所用线缆后的图的邻接表
int cmax;       

struct edge
{
    int x,y;
    int w;
}e[MAX * MAX / 2];  //用来存储各个边的信息，x点至y点的权值为w

int find_set(int a) //查找a所在的集合，回溯时顺便压缩路径
{
    if(a != father[a])
    {
        father[a] = find_set(father[a]);
    }
    return father[a];
}

void Union(int x,int y,int w)   //合并x和y所在的集合，并用cmax记录所有边的权值之和
{
    if(x == y)  return;
    father[y] = x;
    cmax += w;
}

bool cmp(edge a,edge b)   //非降序排序排序函数
{
    return a.w < b.w;
}

int main()
{
    int n,r,i,j,s,t,tmp,k;
    while(scanf("%d%d",&n,&r) != EOF && n!= 0)
    {
        k = 0;
        cmax = 0;
        memset(m,-1,sizeof(m));     //初始化数组
        if(r == 0)      //如果r == 0，直接下次循环
        {
            cout << 0 << endl;
            continue;
        }
        for(i = 0;i < r;i++)
        {
            cin >> s >> t >> tmp;   //输入线缆的数据，连接s和t权值为tmp的线缆
            if(s > t)   //只对m的上三角信息进行存储
            {
                int temp = s;
                s = t;
                t = temp;
            }
            if(m[s-1][t-1] == -1 || m[s-1][t-1] > tmp) m[s-1][t-1] = tmp;   //只保留连接两点的线缆长度最短的边
        }
        //Kruskal算法
        for(i = 0;i < n;i++)
        {
            father[i] = i;
            for(j = 0;j < n;j++)
            {
                if(i < j )
                    if(m[i][j] != -1)
                    {
                        e[k].x = i;
                        e[k].y = j;
                        e[k].w = m[i][j];
                        k++;
                    }
            }
        }
        sort(e,e + k,cmp);
        for(i = 0;i < k;i++)
        {
            Union(find_set(e[i].x),find_set(e[i].y),e[i].w);
        }
        cout << cmax << endl;
    }
    return 0;
}